Presently, there are a variety of vessels designed to contain various fluids such as compressed natural gas (CNG), hydrogen gas for use in a fuel cell, and the like, for example. A common technique for storing the fluid is in a lightweight, high pressure vessel resistant to punctures. Traditionally, such vessels are divided into four types. A Type I vessel is a metal vessel. A Type II vessel is also a metal vessel, the vessel having an outer composite shell disposed on a cylindrical section thereof. A Type III vessel consists of a liner produced from a metal such as steel and aluminum, for example, and an outer composite shell that encompasses the liner and militates against damage thereto. A Type IV vessel is substantially similar to the Type III vessel, wherein the liner is produced from a plastic.
Typically, the liner is manufactured using conventional forming processes such as a welding process, a rotational molding process, and other similar processes, for example. During the welding process, multiple components of the liner are welded together at seams of the components. The weld seams, however, may not be fluid-tight and permit permeation of the stored fluid from the vessel. Further, the welding process limits the types of material which can be used to form the liner. On the other hand, the rotational molding process is slower and produces a liner having an adverse thickness. During the rotational molding process, the liner is formed by disposing bosses in a die cavity with a polymer resin, heating the mold while being rotated to cause the resin to melt and coat walls of the die cavity, cooling the die, and removing the molded liner. The bosses, however, may not properly adhere to the liner resulting in formation of a space therebetween. If the bosses are not properly adhered to the liner, a fluid-tight seal between the bosses and the liner may not form. Without a fluid-tight seal, the contents of the vessel may escape therefrom to the atmosphere. To ensure fluid-tight seals between the bosses and the liner, adhesives, heat welding, and other similar processes may be employed. Alternatively, an adapter device as disclosed in U.S. Pat. No. 7,032,767, hereby incorporated herein by reference in its entirety, may also be used to ensure a fluid-tight seal. Such processes and additional devices may be time consuming and require manual process steps, thereby resulting in an increased cost to produce the vessel.
It would be desirable to develop a vessel and a method for producing the vessel including a thin hollow liner and at least one boss, wherein an efficiency of the method is optimized and a cost thereof is minimized.